This invention relates to display systems for digital oscilloscope in general, and in particular to a time dot display for superposition upon a displayed waveform.
In conventional digital storage oscilloscopes, the information displayed is a series of samples taken from the waveform of interest. The number of samples that may be taken from the waveform is limited by the available memory space. The samples are quantized and stored in memory in the form of digital data. The data is clocked out of memory at a predetermined clock rate, converted back to analog form, and displayed. The display may thus be a series of disconnected dots, or a vector generator may be utilized to connect the dots to produce a continuous display. A popular feature of digital oscilloscopes is the capability of reading out differential time by use of brightened dots placed on the waveform. In prior art systems, the time dots are generated in synchronism with the display clock so that the time dots appearing on the waveform are at the time position points of the sampled data. In positioning such time dots to provide a differential time readout, the displayed dots jump from point to point.